This invention relates to a recording/reproducing apparatus for recording and reproducing video signals and speech signals on or from an optical disc or a magnetic disc as a overwrite type disc-shaped recording medium.
Recently, in a recording/reproducing apparatus for recording and reproducing video signals and speech signals on or from an optical disc or a magnetic disc as a overwrite type disc-shaped recording medium, a technique of perpetually recording live broadcast of, for example, a television program at all times in order to retrogressively view a sole scene which has been overlooked and which it is desired to re-view by the viewer.
Such a recording/reproducing apparatus includes, as shown in FIG. 1, an analog/digital (A/D) converter 311 for digitizing picture signals entering an input terminal I3a, and a synchronization separating circuit 310 for extracting vertical synchronization signal of the picture signal entering the input terminal I3a. The recording/reproducing apparatus also includes a compression circuit 312 for encoding picture data from an A/D converter 311 in synchronism with vertical synchronization signal from the synchronization separating circuit 310 and a first-in first-out buffer (FIFO) 313 for storing the picture data from the A/D converter 311. The FIFO buffer is referred to herein as a buffer for video recording. The recording/reproducing apparatus also includes an A/D converter 331 for digitizing speech signals entering an input terminal I3c and a compression circuit 332 for encoding speech data from the A/D converter 331 in synchronism with a vertical synchronization signal from the synchronization separating circuit 310. The recording/reproducing apparatus also includes a FIFO buffer 333 for storing speech data from the compression circuit 332. The FIFO buffer 333 is referred to herein as a buffer for speech recording. The recording/reproducing apparatus further includes a disc drive 303 for recording video data from speech data from the FIFO 313 for storing the picture data and the speech data from the FIFO buffer 333 for storing speech data on a overwrite type disc 302 in accordance with a pre-set format and for reproducing the speech data and the video data recorded on the disc 302.
The input terminals I3a and I3c are connected to, for example, a tuner, not shown, configured for receiving live broadcast.
The recording/reproducing apparatus 300 also includes a FIFO buffer for storing speech data obtained by the disc drive 303 and an expansion circuit 342 for decoding the speech data from the FIFO buffer 343 in synchronism with the vertical synchronization signals from the synchronization separation signal 310. The FIFO buffer 343 is referred to herein as a buffer for speech reproduction. The recording/reproducing apparatus 300 also includes digital analog (D/A) converter 341 for converting speech data from the expansion circuit 342 into analog data for outputting at an output terminal I3d, and a FIFO buffer 323 for storing video data obtained from the disc drive 303. The FIFO buffer 323 is referred to herein as a buffer for video reproduction. The recording/reproducing apparatus 300 further includes an expansion circuit 322 for decoding video data from the expansion circuit 322 and a D/A converter 321 for converting the video data from the expansion circuit 322 into analog data for outputting at an output terminal I3b. The speech data stored in the FIFO buffer for speech reproduction 343 is also supplied to the disc drive 303.
The output terminals I3b and I3d are connected to a monitor not shown, configured for displaying and outputting a picture derived from the video signals supplied thereto via output terminal I3b and for outputting the speech derived from the speech signals supplied thereto from a speaker, not shown, via output terminal I3d.
The recording/reproducing apparatus 300 also includes a system controller 301 for controlling an output of the buffer for video recording 313 to the disc drive 303, an output of the buffer for speech recording 333 to the disc drive 303, an output of the buffer for speech reproduction 343 to the disc drive 303 and an output of the disc drive 303 to the buffer for speech reproduction 343 and to the buffer for video reproduction 323. The system controller 301 is configured for performing control processing based on a vertical synchronization signal from the synchronization separation circuit 310, a full flag Ffu from the buffer 313 for video recording, an empty flag Fem from buffer 323 for video reproduction and a transfer permission flag Fok from the disc drive 303.
There is provided on the output side of the D/A converter 321 a switch 320 to which are supplied video signals from the input terminal I3a and video signals from the D/A converter 321. There is also provided on the output side of the D/A converter 341 a switch 340 to which are supplied speech signals from the input terminal I3c and speech signals from the D/A converter 341. Under switching control by the system controller 301, not shown, the switches 320, 340 are changed over to the input terminal I3a and to the input terminal I3c during the recording operation, respectively, and to the D/A converters 321, 341 during the playback operation, respectively.
There is also provided on the input side of the buffer for speech reproduction a switch 344 to which are supplied speech data from the compression circuit 332 and speech data derived from the disc drive 303. Under switching control by the system controller 301, not shown, the switch 344 is changed over to the side of the compression circuit 332 and to the side of the disc drive 303 during the recording operation and during the reproducing operation, respectively.
The above-described recording/reproducing apparatus uses a one-shoat playback system of temporarily interrupting the recording operation and a parallel recording/reproducing system of performing the payback operation while continuing the recording operation, in order to permit the user to regressively view the scene he or she has just viewed for a moment.
Referring to FIG. 2, if video signals and speech signals VA0, VA1, VA2, . . . from a tuner receiving the live broadcast, referred to herein as input signals, are supplied to the recording/reproducing apparatus 300, and the playback mode by the one-shot playback system, referred to herein as one-shot playback mode, is set directly after the end of inputting of the input signal VA5 by the key input by the user, the recording/reproducing apparatus 300 momentarily discontinues the recording operation at the same time as the one-shot playback mode is set. At this time, the input signals VA0 to VA5 have been recorded on the disc 302. The recording/reproducing apparatus 300 then reproduces the previously recorded input signals VA2 to VA5 from the disc 302. Subsequently, the recording/reproducing apparatus 300 starts the recording operation for the currently inputted input signals VA10, VA11, . . .
Thus, until the recording/reproducing apparatus 300 is set to the one-shot playback mode, a live picture corresponding to the input signals VA0 to VA5 from the tuner, not shown, for receiving the live broadcast, is displayed on the monitor, not shown. Once the recording/reproducing apparatus 300 is set to the one-shot playback mode, the playback picture corresponding to the input signals VA2 to VA5 is displayed on the monitor. The recording/reproducing apparatus 300 does not perform the recording operation for the input signals VA6 to VA9 entered during the period the playback picture is displayed on the monitor. After the end of display of the playback picture corresponding to the input signals VA2 to VA5, a live picture corresponding to the currently inputted input signals VA10, VA11, . . . is displayed.
On the other hand, if the playback mode by the parallel recording/reproducing system, referred to herein as the parallel recording/reproducing mode, is set for the recording/reproducing apparatus 300 directly after the end of inputting of the input signals VA5, by the key input by the user, the recording/reproducing apparatus 300 reproduces the previously recorded input signals VA2, VA3, VA4, . . . from the disc 302, at the same time as it continues the recording operation.
Thus, until the recording/reproducing apparatus 300 is set to the parallel recording/reproducing mode, a live picture corresponding to the input signals VA0 to VA5 from the tuner, not shown, designed for receiving the love broadcast, is displayed on a monitor, not shown. Once the recording/reproducing apparatus 300 is set to the parallel recording/reproducing mode, the playback picture corresponding to the input signals VA2, VA3, VA4, . . . is displayed on the monitor. Under this condition, the recording/reproducing apparatus 300 performs the recording operation for the currently entered input signals VA6, VA7, VA8, . . .
For performing the above-described one-shot playback mode operation and parallel recording/reproducing mode operation, the recording/reproducing apparatus 300 performs full-field playback operation and frame-skip playback operation during the one-shot playback mode operation and parallel recording/reproducing mode operation, respectively, using a first format comprised of blocks of plural fields constituted by the speech and the video not thinned out on the time axis and a second format comprised of plural blocks constituted by the speech not thinned out on the time axis and video thinned out on the time axis.
For example, if the recording/reproducing apparatus 300 manages picture data and speech data for 8 vertical synchronization periods (V), a format 300a for one block of the first format includes speech data A1 for 1 V, a video data V1 for 1 V, speech data A2 for 1 V, . . . video data V2 for 1 V, . . . speech data A8 for 1 V and video data V8 for 1 V, recorded in succession to the speech data A for 8 V, as shown in FIG. 4A. On the other hand, a format 300b for one block of the second format includes video data V 1 for 1 V in succession to the speech data A for 8 V.
If the recording/reproducing apparatus 300 is not set to the one-shot playback mode, to the parallel recording/reproducing mode nor to the usual playback mode, referred to herein as the usual mode, the recording/reproducing apparatus 300 necessarily records on the disc 302 the video data and the speech data from the tuner, not shown, designed for receiving the live broadcast, in accordance with the format 300a. 
FIGS. 5 and 6 are timing charts for input/output data for the buffers 313, 323, 333 and 343. In FIGS. 5 and 6, each division of video data V-6, V-5, V-4, . . . and each division of the speech data A-6, A-5, A-4, . . . denotes one-field time of video signals.
Referring to FIGS. 1, 4A, 4B and 6, the operation for each set mode of the recording/reproducing apparatus 300 is explained in detail.
First, in the usual mode of the recording/reproducing apparatus 300, the switch 344 is changed over to the side of the compression circuit 332, under switching control by the system controller 301.
The video signals of V1, entering the input terminal I3a during the V1 period, is digitized by the A/D converter 311 and encoded by the compression circuit 312.
Simultaneously, the speech signal A1 entering the input terminal I3c is digitized by the A/D converter 331 and encoded by the compression circuit 332.
The video data V1, obtained on encoding by the compression circuit 312, is stored in the video recording buffer 313. If video data for 1 V, that is V1 video data, is stored in the video recording buffer 313, the full-flag Ffu is set to xe2x80x981xe2x80x99 and routed to the system controller 301.
The A1 speech data obtained on encoding by the compression circuit 342 is stored in the speech recording buffer 343.
Based on the full flag Ffu (=xe2x80x981xe2x80x99) from the video recording buffer 313, the system controller 301 reads out from the speech recording buffer 333 the speech data A-6 to A0 stored therein after encoding by the compression circuit 332. The system controller 301 routes to the disc drive 303 the command and the address for recording data of the disc 302 and the speech data A-6 to A0 read out from the speech recording buffer 333.
Based on the address and the command from the system controller 301, the disc drive 303 records the speech data A-6 to A0 from the system controller 301 on the disc 302.
When the speech data A-6 to A0 has been recorded on the disc 302 by the disc drive 303, the system controller 301 reads out the A1 speech data stored in the speech recording buffer 343 and routes the read-out speech data to the disc drive 303.
The disc drive 303 records the A1 speech data from the system controller 301 in an address of the disc 302 next following the A0 speech data.
The system controller 301 then reads out the V1 video data stored in the video recording buffer 313 and routes the read-out video data to the disc drive 303.
The disc drive 303 records the V1 video data from the system controller 301 in an address of the disc 302 next following the A1 speech data.
If the V1 video data is read out by the system controller 301, the video recording buffer 313 sets the full flag Ffu to xe2x80x980xe2x80x99 which is routed to the system controller 301. If the 1V video data, that is video data for V2, is stored during the next V2 period, the video recording buffer again sets the full flag Ffu to xe2x80x981xe2x80x99 which is routed to the system controller 301.
Thus the system controller 301 reads out the A2 speech data stored in the speech recording buffer 343 after encoding by the compression circuit 332 during the V2 period and routes the read out data to the disc drive 303. The system controller 301 then reads out the V2 video data stored in the video recording buffer 313 from the video recording buffer 313 to route the read-out video data to the disc drive 303.
The disc drive 303 then records out the A2 speech data from the system controller 301 in an address next following the V1 video data of the disc 302 and subsequently records the V2 video data in an address next following the A2 speech data on the disc 302.
By the repetition of the above-described sequence of operations, block data comprised of the A-6 to A0 speech data, A1 video data, V1 speech data, . . . A8 speech data and V8 video data are recorded on the disc 302, in accordance with the format 300a, so that plural block data are recorded in succession.
If, by the key input by the user, the recording/reproducing apparatus 300 is set to the parallel recording/reproducing mode, the switch 344 is changed over to the side of the disc drive 303 under switching control by the system controller 301.
The system controller 301 routes to the disc drive 303 the command and the address in which is recorded an optional block data selected from the block data continuously recorded on the disc 302 as described above in accordance with the format 300a. 
By the address and the command from the system controller 301, the disc drive 303 reproduces video data and the speech data in the optional block data from the disc 302.
That is, in FIG. 5, the system controller 301 routes to the disc drive 303 the playback command and the address of the disc 302 in which are recorded the A-6 to A1 speech data. Thus the disc drive 303 reproduces the A-6 to A1 speech data from the disc 302.
The system controller 301 writes the A-6 to A1 speech data obtained from the disc drive 303 via switch 344 on the speech reproducing buffer 343 in synchronism with the vertical synchronization signals from the synchronization separation circuit 310.
The disc drive 303 then reproduces V1 video data from an address next following the A1 speech data of the disc 302.
After resetting the write address of the video reproducing buffer 323, the system controller 301 writes the V1 video data obtained by the disc drive 303 in the video reproducing buffer 323.
The expansion circuit 322 resets the reading of the video reproducing buffer 323 in synchronism with the vertical synchronization signals from the synchronization separation circuit 310 for reading out the V1 video data stored in the video reproducing buffer 323 eight times on end and for sequentially decoding the read-out video data to route the decoded video data to the switch 320.
At this time, the expansion circuit 342 decodes the A-6 to A1 speech data stored in the speech reproducing buffer 343, in synchronism with the vertical synchronization signals from the synchronization separation circuit 310, for outputting the decoded speech data via switch 340 and output terminal I3d to the speaker.
Thus, a playback picture corresponding to the V1 video signals is displayed for eight fields on the monitor, while the speech corresponding to the speech signals A-6 to A1 are outputted via speaker, not shown.
If the video data for 8 V and the speech data are reproduced as described above, the recording/reproducing apparatus 300 performs the recording in accordance with the format 300b. 
That is, the system controller 301 reads out A2 to A9 speech data encoded by the compression circuit 332 and stored in the speech recording buffer 333 during the V2 to V9 period. The system controller 301 routes to the disc drive 303 the command and the address next following the V8 video data of the disc 302 and the A2 to A9 speech data read out from the video recording buffer 333.
Based on the address and the command from the system controller 301, the disc drive 303 records the A2 to A9 speech data from the system controller 301 in an address next following the V8 video data of the disc 302.
The system controller 301 then reads out V9 video data from the system controller 301 in an address next following the A9 speech data on the disc 302.
Thus, the A2 to A9 speech data and the V9 video data are recorded on the disc 302 in accordance with the format 300b. 
The system controller 301 then routes to the disc drive 303, in synchronism with the vertical synchronization signals from the synchronization separation circuit 310, at a timing of the start of the eighth playback of the V1 video data, an address by which the 8V speech data of from A2 to A9 have been recorded on the disc 302. This enables the disc drive 303 to reproduce the A2 to A9 speech data from the disc 302.
The system controller 301 then causes the A2 to A9 speech data from the disc drive 303 to be written via switch 344 in the speech reproducing buffer 343.
The disc drive 303 then reproduces the V9 video data from an address next following the A9 speech data of the disc 302.
After resetting the write address of the video reproducing buffer 323, the system controller 301 causes the V9 video data reproduced from the disc drive 303 to be written in the video reproducing buffer 323.
After read-setting the video reproducing buffer 323 in synchronism with the vertical synchronization signals from the synchronization separation circuit 310, the expansion circuit 322 reads out the V9 video data stored in the video reproducing buffer 323 eight times on end and sequentially decodes the read-out data to output the decoded data to a monitor, not shown, via D/A converter 321, switch 320 and output terminal I3b.
The expansion circuit 342 sequentially decodes, in synchronism with the vertical synchronization signals from the synchronization separation circuit 310, the A2 to A9 speech data stored in the speech reproducing buffer 343, and outputs the decoded data via D/A converter 341, switch 340 and output terminal I3d to the speaker.
This, a playback picture corresponding to the V9 video signals are displayed for 8 fields on the monitor, while the speech corresponding to the A2 to A9 speech signals is outputted by a speaker, not shown.
The above playback operation is repeated until xe2x80x98stopxe2x80x99 of the parallel recording/reproduction is commanded by the key input by the user.
In the recording/reproducing apparatus 300, block data conforming to the formats 300a or 300b are continuously recorded on the disc 302 and reproduction is performed beginning from a specified one of the plural block data recorded continuously on the disc 302 which is in accord with the format 300a. Thus it is supervised by the system controller 303 whether the reproduced block has been recorded in accordance with the format 300a or in accordance with the format 300b. 
With the above-described conventional recording/reproducing apparatus, such as the above-described conventional recording/reproducing apparatus 300, the number of fields of video data of the format 300b is one, that is the number of frames during the parallel recording/reproducing mode is one for the number of fields in a block of the format 300a, as shown in FIG. 4B. Thus, if 8 V video data and speech data are managed, the playback operation is xe2x85x9 frame-skip operation during the parallel recording/reproduction, resulting in an unnatural picture obtained by the recording/reproducing apparatus.
If, for overcoming this problem, the number of reproduced frames is simply increased in carrying out the parallel recording/reproduction, it becomes necessary for the recording/reproducing apparatus to access the recording point and the playback point on the disc alternately a number of times equal to the increased number of the playback frames. Thus, much time is consumed in the seek operation for the disc such that the recording and reproduction cannot be completed within a pre-set time.
Moreover, with the above-described recording/reproducing apparatus, since the compression and expansion need to be performed on the video signals at all times for the parallel recording/reproducing mode, it is necessary to provide a compression circuit separately from the expansion circuit. Since these circuits are costly, the recording/reproducing apparatus cannot be reduced in production cost.
It is therefore an object of the present invention to provide a recording/reproducing apparatus in which a satisfactory playback picture can be obtained for the parallel recording/reproducing mode.
It is another object of the present invention to provide a recording/reproducing apparatus in which production cost can be reduced.
The present invention provides a recording/reproducing apparatus in which video signals and speech signals are recorded in synchronism with each other on an overwrite type disc-shaped recording medium based on a selected setting of the processing mode, and in which the video and the speech are reproduced in synchronism with each other from the recording medium having the video signals and the speech signals recorded thereon. The apparatus includes storage means for storing the video signals obtained from the recording medium, decoding means for decoding the video signals stored in the storage means, holding means for holding the video signals decoded by the decoding means and control means for controlling the address management and data transfer for the recording medium and for controlling the overall operation of the apparatus. In the processing mode in which the recording and the reproduction are carried out alternately so that reproduction is performed while the recording is going on, the storage means stores plural fields of the video signals and the holding means performs interpolation of video signals.
In the recording/reproducing apparatus according to the present invention, the signal processing means has the expansion function of decoding the video signals stored in the storage means, and the compression function of encoding the video signals recorded on the recording medium. In the processing mode in which the recording and the reproduction are carried out alternately so that reproduction is performed while the recording is going on, the control means switches the operating timing of the entire apparatus and switches between the expansion function and the compression function of the signal processing means so that the recording operation and the reproducing operation will be carried out alternately.